Windshield wiper system



Septa 30, 952

R. FREEDMAN ET AL WINDSHIELD WIPER SYSTEM Filed Oct. 4, 1945 2 SHEETS--SHEET l Sept. 30, 1952 R. FREEDMAN ET AL 2,632,343

wINDsHIELD WIPER SYSTEM Filed 0G12. 4, 1945 2 SHEETS--SHEET 2 /NVE/roes: RuooL/JH FREEDMn/L JOHN 5. Duse,

QTToP/VEVS.

Patented Sept. 30, 1952 Rudolph Freedman, University City, and John E. Dube, Chesterfield, Mo., assignors, by mesne assignments, to Alco Valve Co., St. Louis, a corporation of Missouri I,

Application October 4, 1945, Serial No.v 620,31?

This invention pertains to improvements in hydraulic windshield wipers, and concerns itself primarily with apparatus providing forthe parking of the wiper blades semiautomatically.v

It is a general aim of theinvention to provide a hydraulic windshield wiper device having means for moving a wiper blade to a selected position semiautomatically and maintaining the blade in this position when the device is not operating.

More specifically, it is an object of the invention to provide a hydraulic windshield wiper device having a speed control valve capable -of controlling the flow ofI fluid toits wiper units in a manner such as to move the blades ofthe wiper units to a selected position semiautomatically. for maintaining them in this position, commonly referred to as their parked or parking` position.

Another object of vthe invention is to provide a hydraulic Windshield wiper system with animproved speed control valve manually operable after the metering arrangement thereof has been moved to stop the wiper units to move the wiper blades to a parked position.

It is a further object of the invention to provide an improved speed control valve for a hydraulic windshield wiper system having, in addition to a metering valve, a parking Valve operable after the former has been closed to supply fluid to a wiper vunit line of the system in ya manner such as to move the respective wiper blades to a parked position. A still further object of the invention is to provide an improved hydraulic windshield wiper system having manually operable means to bypass high pressure fluid around the systems control unit into a wiper unit line, after stoppage of uid to the control unit, for the purpose of moving the Wiper blades of the systems wiper units to a parked position and thereafter maintaining them in this position by repeated applications of high pressure fluid. l

Yet another object of the invention is to provide a hydraulic windshield wiper system in which the wiper blades of the systems Wiper units may be moved to a parked position and thereafter maintained in this parked position by either Inechanical or hydraulic locking means.

Other objects and advantages will become apparent as the description proceeds and a more comprehensive understanding of the invention 3 claims.. 01. 121-158) Will be afforded 4from the following detailed description when considered in-fconjunctionwit the accompanying drawings in which: Fig'. 1 is a plany view of a hydraulic 'windshield `wiper system embodying theiinstant invention;

Fig. 2 is a side elevational View of a speed 'control valve' employed in the `system illustrated in Fig. 1 taken along-the line 2--2 thereof;

Fig.r 3 is a vertical sectional view of the speed control valve shown in Fig. *2'taken' along theline 3--3thereoi`;ml y

Fig. 4 is a diagrammatic illustrati-on of an im-l proved control unit for the system illustrated in Fig. 1 showing thevarious parts thereof; I

Fig. 5 is a vertical sectional view illustrating-a hydraulicl motor adaptable to thewiper units em:-l ployed in the system; and l' Fig. 6 -is a vertical'sectional lView of a modified form of a hydraulic'motor also adaptable for use'in the systems wiper units.

A hydraulic Windshield wiper' system embody.- ing the instant invention isillustratted in Fig'. l and contemplates the use'ofv a'pair of wiper units II and I2, a control unit I3,` and va speed control valve I4, that acts'as a mainvalve for the system. Fluid under'pressure is 'admitted to the speed control valve I4 througha liney I5 where it is metered for transmission through a line I6 to the control unit I3. From the' latter device,'a line I'l supplies fluid to thewindow Wiper' unit I I and a line lI8 ysupplies fluid to the window unit I2. Both units are connected by a line I9 which transmits fluid therebetween, and uid from each of the units is exhausted through the control unit I3 to a line 20, which returns it to a reservoir (not shown). From the speed control valve "I4 a line 2l is connected into the line I1 feedingthe wiper unit II, which provides for the'bypassing of high pressure fluid from the line I5 around the control unit I3 and into the'wiperline I1.

With the system just described, uid under pressure is directed by the control unit I3 alternately to the hydraulic motors M and M of the f Wiper units II and I2, respectively, -in a manthe windshield.

ner such that their wiper blades 24 and 25 are moved back and forth across sector areas of the windshield 26 to maintain the same clear vof theelements and provide clear visibilitythrough As will now be described, the motors-M andMf may take either one of the two illustrated forms, depending upon system requirements. As is more fully described in a copending application for a hydraulic windshield wiper system, United States Serial No. 620,318, led October 4, 1945, by the instant inventors, now Patent No. 2,516,558 issued July 25, 1950, the form of the hydraulic motor illustrated in Fig. 5 contemplates the use of a mechanical locking means operable to lock the motors piston in a xed position to in turn lock the wiping blade of the wiping unit in a parked position.v This; improved 'motor embodies novel features which permit the locking of the piston without resort to return lines and offers a diierent locking arrangement over the basicunit illustrated in Fig. 6 which utilizes hydraulic..

locking means.

1944, by Howard E. Rose,V nowvv Patent No.

2,516,594, issued July 25, 1950, the hydraulic motor 22 illustrated in Fig. 6 comprises a cylinderv 21 in which a double-acting piston 28 is operative. The latter element is provided on` its ex?- ternal surface with a rack 29 which is meshed with. an pinion, zfxed: tol` af splined' shaft 3 I f on which ai* windshield wiper?"` arm 1;32* is carried. Located withni tirerpistorr'Z'Bisra'. double-acting relief' valvef 33'.;- The vrelieffvalve'has a 'springpressed valve? element at each; end', eachabutting a; tubular: slide. shovvmgin'fthe copendingf application,. each: spring, resists flow through the piston, in its: respective' direction, until stoppagezofi piston 28 movement; permits' adequate. hydrauliopressure' buildup to: overcome the spring. The unit is also provided/@within its; end connections 34 and'. 35,:with; dashpot ,check valvesy 36y andi 3:15' anda the: unit is I supplied. fluid by connecting lines suciras', I-'I and; t9: threaded respectively into'its-fend'.V connections 34 and 35. Under" the forces 'of iiuidf. pressures: supplied' by the lines Il and I9, the. pistorrzi-l offthe .motor ismoved backward fand-forward ltorocle the shaft 317,' the Wiperarm' 32;.andg; incidentally, the wiper blade 24, as will be-describedinconnection with L thefsystems operation. p, Y K

hydraulic motor 23; illustrated in. Fig. 5, isf similar' in.V construction; tov that illustratedy in Fig'. 6:. The similarity of the'two motorsawill be: accenu-iatectv by designating` its similar parts byprimed-:reference numerals.. Thus-the motor 2:3 has a. cylinder21 infwhich; ai double-acting pistonv 21B' isf operativer, The. latter elementis pro-vided onf its external surface' withf a` rack 29. whichfmeshes-v/ith apinion: 35 xed toa splined shaft. 3l.' on which.r a windshield wiper arm. 32 is: carried'M Located, within. the piston. 28.' is a double-acting' relief valvev 33'.. The unit. is. also provided with end. connections. 34.' and. 35.' into which lines such as Il and I9 are. connected for the purpose of. supplying, fluid under pressure. tothe vpiston 2&5. Also carried within the end connections 3.4' andv 35 are the dashpot check valvesy 36' and. 31'..

In addition, the: casing 2.1" is pro/videdwith a boss a'within which a` locking, piston 39 is sl-idably retained by a cap. 4I. screwed. onto the boss' 38. A recessli?Y in the lockingy piston4 39 forms a retainer for a compression. spring 43 which, seatingagainst an internal facev of the capY Hf, biases the locking piston 39- in a man.- ner suchas to movea lug 44, forming part. of the latter element,l intoy engagement in. aA groove 45 within the piston 28. The latter element has; a portion: of its:k surface` undercut. to: provide a passageway 46 communicating with' a notch v41 through which uid under pressure is transmitted to the chamber 48 above the locking piston 39. A similar notch 49 permits iiow of iiuid from the opposite end of the piston into a chamber 5I, also above a portion of the locking piston 39. Under the influence of fluid admitted by either of the lines I1 or I9, the piston 39 is thus movable against the compressive forces of the spring 43 to remove the lug 44 from the notch 45 in the piston so that the latter element is free?y to.- move3 within thecylind'ei'. 21V. Conversely; when fluid pressureV is removedfrom the unit, the spring 43 is operative to bias the locking piston upwardly so that the lug 44 thereof moves. to. engagement with the groove 45 of the piston and' provides a positive mechanical lock for1 the; piston in. this position.

i 'Ilieir control. u nit-Y I3 which directs the ilow of fluidf` to the` hydraulic motors M and M in a manner tofreciprocate the Wiper blades 24 and 25A comprises a valve body 55 in which there is channelled a plurality of conduits interconnectingfour valve cavities containing four hydraulically operated valves. Under iluid pressure received4 from. theline I5 three ot these valves are., manipulated to alternateiy apply pressure torthe motors M. andlvlz,l the saidziiuid being exhaustedffromf the motor. not.- receiving highv pressurei'uid; through the: controlA unit' I3 andzthe'line-`2`0-baclcto storage..

As previously stated,high pressure uuid-.is admitted' through; the line |16". This liner in; turn is connected to: a. valve; cavity E61-byv meansof a conduit: 5l. Within; the cavity 56;'. a sliding valvey 58: is. operative'. This'- valve;y termeda doubleeacting relief valve;- is: biased to its neu'- tral positionby a spring 591 but is otherwise hydraulically operated. r'Ihrough its. operation', asecond; sliding valve lil-.1 known. asf a, pilot; valve'. is,` controlled'. valve; is entirelyv pressure operated and` functionsinav valve. cavity 6.2;. A third; sliding valve described as; a directional valve 6:3; moves.- within a valve cavity 64;t and controls. the flow of high pressure fi-uidz to.` either cfa-the lines I1; or HiL depend-ing upon which' motor is tolreceive it. With-in a. fourth valve cavity 65, a parking valve 66 isoperativeand: is biased toits illustrated position; by means of a spring 6.1.. Thisvalve operates conjunction withr a parking valve in theY speedz control valvev I4, as will be described moreVV fully inv connection with the= systems operation.. Y

The lines ISI and tu are connected with the valve cavity by two conduits. 585 and 69 respectively, and the exhaust line 29- communicates withthe valve cavity 55 by meanse of;V a conduit TI..A Each of the valvecav-ities hasinterconnecting conduits andeach., of; the various valves has reduced sections which perm-it a, fioW ofl ilu-id around. that valve.. The pointsofvv entry of the various conduits. into the valvecavities. form ports. which are opened and closed, depending ori-.the particular section of the valve moved over them.. Conduits. are also, provided to` apply pressure to the end sections. of the. various valves to effect their movement in. their respective cavities.

The: speed control valve I=4 as a unit. hasAl two functions, one. of. which is. to. control: the. rate of' a flow of fluid. to the. control unit [3, which, in turn, controlsthe speedy at4v which the. Wiper blades. aremoved. across` the windshield, and the other is toI park the. blades. in a selected posi.- tion where they are maintained when the. system is not operative. As illustrated in Figs. 2 and 3, this device comprises a valve body 12 provided with a pressure inlet opening 13,/ a pressure outlet opening 14 and a parking outf l'et 15. Each of these portions of the valve body isV tapped and threaded to receive, respectively',y The valve body 12. is

against a shoulder 11 formed in the bore of thel valve'body. The metering valve 15 has a cupshaped upper end fitted securely onto e, threaded stud 18 which operates within a cap 19 closingthe vertical bore of the valve body. To the stud 18, 'a

thumb wheel 8| is attached. Operation of this Whe-e1 in e. clockwise direction moves the studY 18 downwardly against the valve 15 to close the same against 'its seat. Opposite movement lifts -vthe valve 15 from its seat 11 to open and permit high pressure fluid in the line I5, a port 82, and a chamber 83,'to flow Iaround the valve 15 into a'chamber lgthrough a port 85 communicating with vtheoutlet opening 14 into the line I6. f

The stud 18, as well as the metering valve 15', is bored to receive a parking valve stem 86. This stem engages a packing ring inthe cup-shaped upper end of the valve 15. This stem 86 is providedfat its lower end with a reduced section81 which, together with the bore of the metering stem 15, forms a port or chamber 88 connecting the chamber 83 with a chamber 89. Thus, as the parking vvalve 16 is moved downwardly by the valve stem 86, it is opened and high 'pressure'fluid from the inlet opening 13 is permitted to f lo'w through the chamber 88 around the valve 16 into the chamber 89 from which point it flows through a port.9| to the parking outlet 15 and into'ithe line 2|. For operation of the parking valve-16, a button 92 is fixed to the stem 86 by means of two nuts 93' and 94.- The thumb wheel 8| is recessed to retain a compression spring 95 which seats against the thumb button 92 and the thumb wheel 8|. This spring is operative to maintainthe parking valve 16 closed.

Operation For the purpose of describing its operation, the system will be assumed to have been stopped'after a previous use. In this condition, Ithe wiper blades 24 and 25 will occupy their parked position to the left, as illustrated in Fig. 1, the pistons will be at the right (Fig. 5), and the entire system will be considered as being filled with fluidjand properly bled. Further, the various valves o f the control unit I3 will occupythe positions illustrated in Fig. 4. As a further aid to the description of the systems operation, quantitative Vfluid pressure values will be used although it is to be expressly understood that the system is not limited to any particular operating pressure or pressures nor to any particular pressure-exerting medium.

When it is desired to place the system in operation, high pressure fluid, which is impressed upon the system from a proper source through theline I5, is admitted thereto by opening the metering valve 15 of the speed control valve III. The opening of this valve is accomplished by turning the thumb wheel 8| in a counterclockwise direction, and the amount of fluid which is admitted tothe system, depending upon the degree to which" the metering valve 15 is opened, determines the'speed at which the system will operate. From thespeed control 'valve' I4 metered fluid is transmitted through the line I6 to the control unit I3. With the relief Avalve 58, the pilot valve 6I and the directional valve 63 positioned as illustrated, the work line I8 will be connected to the exhaust, `or

low pressure line ZILand-the work line I1 will be closed vby the parking valve 66. However, upon the admission of high pressurefluid into the control unit I3, the parking valve 66 will receive high pressure fluid on the left end thereof and will move to the right against the forces of the spring 61. Fluid pressure will hold this valve in this position as long as the system is operating. When in its open position, the parking valve 66 will be.

moved so that both of the lines I1 and I8 are ported to receive fluid pressure under the control' of the directional valve 63, and the line I8 is cut off from the exhaust line 2D.

Starting from a previous parked position, the

ing valve is opened, high pressure fluid will be transmitted to the line I1 wherein a pressure will be developed whichlwill operate to attempt to move the pistons 28 to the right and the wiper blades 24 and 25.to the left. l Since the pistons of the hydraulic motors M and M are already moved to their extreme right hand position', pressure of the fluid in the line I1 builds up against the total force of the valve-resisting springs of the pistons 28, to a value approximating four hundred and fifty pounds per square inch, which is equivalent to the active forces of the spring 59, of the relief valve 58, but'l kwhich is below the total forces of lall springs acting against the valves of the pistons 28. This pressure is applied also from the line I1 through the bypass passage 99 in the control I3, to the left end of the relief valve 58 which is normally held in a middle position by the spring 59. Since this pressure is sufficient to overcome the action of the spring 59. the relief valve 58 is moved to the right and fluid is ported to the right of the pilot valve 6| moving the same to the left. As the pilot' valve 6I is moved to the left, high pressure fluid is ported against the directional valve 63,` likewise to move it to the left.` Since fluid from the pilot valve to the directionalvalve is preferably restricted in its flow, as by a restriction IIII) in each' passage to the respective vends thereof, the valve 63 moves more slowly than nected with the low pressure line 20 causing the pistons of the hydraulic motors M and M' to move to the left and reverse the Wiper stroke. A's soon as this occurs, the double-acting Vrelief valve 58 is no longer pressure actuated, and the same is moved to its neutral or middle position by the spring 59, thus hydraulically locking the pilot and directional valves to the left. Under assumed conditions, the maximum operating pressure of the system is approximately four hundred pounds per square inch,`which is insufficient to shift the relief valve 58 from its neutral position, the spring 59` being selected to require a pressure of four hundred and fifty pounds per square inch to move :the valve. When the wipers and pistons reach the ends of their strokes, there will be a similar pressure built up `that will act upon the right end of the relief valve, reversing the control I3 and the pistons. j

i Since both of the double-acting relief valves of either selected hydraulic motor are set for operation-at two hundredandriiftyspoundszper squareiricllfthereisa pressure drop across thei two'approximating five hundredzpounds' persquare. inch., Fur-ther, the.' piston 'ofslthemotor M'v mayfre'ach the. end: of its; stroke prior; to the' time 'thegmotor M' reaches Ithe end'` of its stroke' when. pressuregis being portedthrough-the line I8; The converse maybetrue When highl pressureiluid. is being directed through-.the line Il: V.This Will bertruesto:y the extent-oi leakage of liquid aroundtheremote pressure through the interconnecting line I-r9f tov the other hydraulic motor'of.y the. secondfwiper.-

unit and. move its blade-in synchronism'f. As 4both ofsthe' pistons reachY their extreme stroke,1 either' tothe left orto the. right, they oier `a combinedv pressure' drop of approximately ve hundred' poundspersquare inch, and fluidi-no longer lilovvs' throughv the system. Accordingly', pressurebulds' up'in one of the linesrto--the required-four hundred and iifty pounds per square inch,'suiiicient toioperate-the'frelief valve 58r and theentiresequenceo-f operation' is repeated. Thereafter, and under the` control'oi the control v-unit I3, high pressure 'huid is directed `alternately to the lines II; and I8, and the Wiper blades 24- and-25 are'moved-over the' windshield 26. y. 'z r.

When itis desired togstopthe sys-tem and also to move the Wiper blades4v 2liand25 tol a selected parked position, the metering valve l5-.ofthe speed control :,valve IIIv is rst closedby turning the thumb- Wheel 8-I ina clockwise direction. y To operatertheiparking system most readily, this should bedone-When the Wiper blades are vmoving to the left-, tliat is when the directional valve 63 is to the right as illustrated,c and -high pressure. uid isfbeing ported to the line.l Il. This" operation cutsj oiv high pressure fluid to the. system, and theparking valve 56 of the control'. unit I3 is movedunder the forces off the spring 61- to its illustrated position Wherefit will be noted -theiline I'I is closed andthe line I8 is opened to'exhaust. .After the system has thus been. brought to rest by closing of the metering valve, the bladesv of. the'w-iper units are parked. .by manual operation oivgthre parking valve- 16. Here the operator delv presses the thumb button 92 against the forces of thespring S5 to open the valve 161. This operation-,ports fluid from` theghigh pressure line I5, around.A .the parkingvalvell, into the line 21.. Since the line II is closedy at the `control unit |13@ byA theparkingvalve 66, high pressure iluid is active against the piston ofgthe hydraulic motor. wiper. unit IIwhich moves the blade thereof to the illustrated position where it may be lockedeither hydraulically or mechanically, depending upontl'ie hydraulic motor selected forthevwiper unit'. 'Under the influence of high pressure fluid, the relief valve of the motor M is opened to trans-- mit i'l'uidl through the line I9, to the motor M', and," through similar operations, the wiper blade 25v vis moved to. its parked position.. Since the line I8A isopened to exhaust by the parking valve. 66, uid displacement in this part. of the system :is provided for. y y l 'Asl previously stated, the wiper blades and various units maybe movedA toltheir selected parked positionand locked in this position either mechanically or hydraulically,v y

,Ifmechanical locking is desired. the hydraulic mo.tors;of,the-wiper units I I and I2are selectedttm includefthe embodiments 4of thea invention as il.- lustrated-in Fig. 5, Hereithepiston 2,8 is moved, to an extreme position, depending uponlits-v ar.-` ra'ngementin the system, by manipulation ofthey parking valve '161v Thereafter, as pressure iscut: oilwhen-the valve 'I6 is closed, thespring7 A43.*isi operativeto m'ove'the locking pistonJ 439into enf gagement With-the-slot 4 5 in the piston 2'8-1and thereby lock the blade of the unit` driven bythemotor in its'parkedV position. Movement oiwthe piston!!` displacesiv a small amount of liquidin .the system. However;` this displacement is providedf for .by the opening-'of one line of `the hydraulic motor to exhaust through the-*operation of the. parking-valve'. s `5 A 'If a hydraulic motorfsuch as that. illustrated Fig. .6 is used, hydraulicy locking of the Wiper units in their'parkedl positionis resortedto. Thus;`

through operation ofv -the parking valve 16, high pressure fluid. is` trapped in the. system inthe-lines.v I'I andZI betweenl the control unit I3, thespeed'; control valve I4 vand themotorMby the parking- I valve 66 of the control unit I3.' This pressure-,acteing'ag-ainst lthe pistons of the variousunits'retains them locked hydraulically. Aswillv be apparent to those skilledin the art, this pressure willy be 'subject to decay since uid will pass through the Wiper -units, the line I8.and= on-.to. ex haust4 throughthe control unit I3. Whenthe pressure f drop reaches Aa point, however, lsuch as: to-permitA the movementA of the Wiper'blades from their. parkedvposition,l allthat is required is ,ane other injection of .high pressure fluid into the trapped portion of the system-by 'openingI the parkingvalve-l'. 1

WhileV the particularl embodimentofi the; invention has been illustrated and described, itzwill beapparent that .the invention is subject toy other modifications and changes and; accordingly,;;all such modifications and changes to` which the-in;- vention-is susceptible are considered-.tol bef'covered' as if described, and the invention'- is to be limited.: solely by the appended claims.

What is claimed is:

l. In a mechanism of the kind described, a fluid motor including a cylinder and a piston reciprocable therein,. a yiuid pressure operated reversing valve, a pair of fluid pressureworklinesirom the reversing. valve to the opposite ends of. the cylinder respectively, vthe reversing valve havingI a high pressurey inlet and a low ypressure outlet connectiblel with the pair of iluid pressure lines respectively,.and means for reversingthe last-named connections in. responsey to. fluid pressure conditions resulting from obstruction to travel of the. pistona main valve in the high pressureV inlet for regulating high pressure flow to the reversing valve; a bypass. valve for connecting the high pressure linek torone of the Work lines,v andto bypassv the vreversing valve; and a. parking valve in the two work lines movable from. a rst position to open both work lines to a second position. to close the one Work line. interconnected with the bypass and to open the other work. line.. to the low pressure outlet, means normally urging the parking valve toward ,second position, and means responsive to predetermined fluid pressure at the high pressure inletto the reversing valve,v to displace the parking valve `to itsl rst position. l

2 The combination of claim l, wherein the main valve comprises a housing With a main .inlet, a main outlet for connection withthereversing valve and a bypassroutlet, a .main valve for 9 opening the inlet to the main outlet, and a bypass valve for connecting the inlet with the bypass outlet.

3. The combination of claim 1, wherein at least one of the two last-named valves is a balanced valve and has pressure-operatable actuating means.

RUDOLPH FREEDMAN.

JOHN E. DUBE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Larking Aug. 6, 1889 Number 

